New polymeric membrane cadmium(II)-selective electrodes using tripodal amine based ionophores

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Development of selective ion-selective electrodes (ISEs) is crucial for accurate heavy metal detection.
• Cadmium (Cd2+) poses significant environmental and health risks, necessitating sensitive monitoring methods.

Purpose of the Study:

• To design and fabricate novel neutral carrier-based PVC membrane electrodes for selective Cd(2+) detection.
• To investigate the structure-property relationships of synthesized ionophores for optimal electrode performance.

Main Methods:

• Synthesis of ionophores with varying topologies, donor atoms, and lipophilicity, including tripodal amine (TPA) units attached to anthracene and calix[4]arene scaffolds.
• Incorporation of synthesized ionophores into plasticized PVC membranes to create Cd(II) ISEs.
• Optimization of membrane composition (ionic sites, plasticizers) and evaluation of electrode selectivity, response characteristics, and operational stability.

Main Results:

• Ionophore IV, featuring two TPA units on a calix[4]arene core, exhibited the best selectivity for Cd(2+).
• The optimized electrode using ionophore IV demonstrated a Nernstian slope of 29.4±0.6 mV decade(-1), a wide working range (1.6×10(-6)-1.0×10(-2)M), fast response (10s), and stability for over a week.
• The electrodes operated effectively within a pH range of 6.0-9.0 and were successfully applied to determine Cd(2+) in CdS quantum dots solutions and wastewater samples.

Conclusions:

• The developed PVC membrane electrodes based on ionophore IV offer a highly selective and sensitive platform for Cd(2+) determination.
• The study highlights the significant impact of ionophore structure on electrode performance, providing insights for designing advanced chemical sensors.